code: def _outsize(x):
      if isinstance(x, chainer.utils.collections_abc.Iterable):
          if len(x) == 2:
              return (None,) + x
          else:
              return x
      return None, x, x
  
file_path: chainercv/chainercv/functions/ps_roi_average_pooling_2d.py
imports: from __future__ import division
  import numbers
  import numpy
  import six
  import chainer
  from chainer.backends import cuda
  from chainer import function
  from chainer.utils import type_check
label_desc: Use image node_id 1 for calling a global function with example usage: _outsize(x) and returns: None,  x,  x, unknown, x